Cooling means for electrical induction apparatus



0a. 28; 1941. E A, EL E 2,260,833

COOLING MEANS FOR ELECTRICAL INDUCTION APPARATUS Filed Dec. 1, 1959 2Sheets-Sheet 1 Inventor: Ernest A. El ge by W MMZM His 'Atbor-ne g.

Oct. '28, 1941. E. A. ELGE 2,260,833

COOLING MEANS FOR ELECTRICAL INDUCTION APPARATUS Filed Dec. 1, 1939ZSheets-Sheet 2 Inventor: Ernest, A. Elge,

His Attorneg.

Patented Oct. 28, 1941 UNITED. STATE s PATENT OFFICE COOLING MEANS FOR.ELECTRICAL INDUCTION APPARATUS Ernest A. Elge, Pittsfleld, Masa,asslgnor to G eneral Electric Company, a corporation or New YorkApplication December 1,1939, Serial No. 307,066

2 Claims.

This invention relates to cooling of the electrical windings ofinduction apparatus and while it is not necessarily limited thereto, itis particularly adaptable to reactors and especially to current-limitingreactors.

Current-limiting reactors are usually provided in an electrical powercircuit for preventing the current flowing therein from increasing toabnormallyhigh values upon the occurrence of a system fault such as ashort circuit. Such reactors usually comprise a plurality of woundlayers of copper conductors suitably supported in a spaced relationshipby a non-magnetic structure a squirrel cage type rotor and a statorstructure comprising a plurality of magnetic flux collector arms sodisposed with regard to the magnetic field of the reactor that a certainportion of the V flux created thereby passes through the arms forenergizing poles adjacent the rotor. The pole faces are slotted andprovided with shading coils so that a revolving'iield is created forcausing rotation of the rotor. By this arrangement the motor and hencethe fan is driven at a speed directly proportional to the load carriedby the of insulating material. Inasmuch as the current carrying capacityof the reactor is limited by the heating characteristics thereof, asupporting structure is provided with a plurality of openings to allowfree circulation of airor other cooling iiuid therethrough. In thecaseof enclosed reactors submergedwithin an oil container, the heat iscarried from the conductors by convection currents which heat is thendissipated from the side walls of the container or from suitablyarranged heat exchangers' By providing means for increasing thecirculation of cooling medium over the conductors, the current carryingcapacity of the reactor may be considerably increased, A

or the size and amount of material used in the reactor structure may bedecreased and the cost I of manufacture therepi correspondingly lowered.

It is a general objectof this invention to provide a new and improvedimpeller means for increasing the circulation bf cooling medium over Ithe conductor windings of electrical induction apparatus. i

,It is a further object of the invention to provide a new and improvedimpeller means for ins in section of the cooling fluid impeller motorillustrating certain structural details thereof;

.' Fig. '5 is an enlargeddiagrammatic plan view of the motorillustrating certain features thereof; Fig. 6' is a diagrammatic viewsimilar to Fig. 3 with the fluxpath plottedyFigs. '7 and 8 arediagrammatic views similar to Fig. 6 illustrating modifications ofthe'invention; Fig. 9 isa plan viewof a reactor provided with a coolingfluid impeller motor according to a preferred modiii cation of theinvention; Fig.10 is an enlarged view of the impeller driving motorillustrated in Fig. 9.

Referring to the drawings in Figs. 1, 2 and 3, is

I shown a typical air core reactor l9, being of the creasing thecirculation of cooling medium over the windings of electrical inductionapparatus which means comprises a minimum number of parts and. isautomatically operable in, accordance with the load on the reactorwithout the use of auxiliary control apparatus.

More specifically, it is an object of this inven'' tion to provide anew'and improved motor for use with electrical induction apparatus whichmotor is adapted to be energized from the magnetic fluxproduced by thewindings of the induction apparatus without the use of special statorenergizing windings.

In the illustrated embodiment of the invention an air-corecurrent-limiting reactor is provided with a suitably arranged fan forincreasing the circulation of coolingmedium over the conductor turns.The motor for driving thefan comprises I type specifically described inPatent No. 1,317,003

Creighton, issued September 23, 1919, and assigned to the GeneralElectric Company, the assignee of the present application. The reactoris made up of a plurality of similar ring shaped sections 20 eachsection comprising a single coil or layer of a conductor embedded in andsupported'by the spider portions flextending radially between the outerring portion 23 and the inner ring portion. The conductor-coils are Isuitably connected together in series and provided with terminals (notshown) for connection to an electrical circuit. The plurality of.stacked sections 20 are mounted upon a ring shaped base portion 25 whichin turn is supported by suitable insulators 26. Suitably spaced openings21 and 28 are provided between the outer and inner ring portions 23 and2!; respectively, of the ad-' iacent sections to allow free circulationof ventilating air into the reactor structure for cooling the conductorcoils thereof. The inner walls of the aligned inner rings 24 and base 25define a central opening 29 extending vertically through the reactorassembly for further enhancing the circulation of ventilating airthrough the structure. As described in the above mentioned patent, thesupporting structure comprises a suitable insulating plastic such asconcrete.

For improving the circulation of cooling medium, such as air, throughthe reactor structure, provide an impeller or fan within the lowerortion of the central opening 29 and driven by motor In accordance withmy invention the motor 3i comprises a stator structure includa pair or"flux collecting arms 32 and 33 and ntermediate rotor 34 which may be ofthe irrei cage As shown more clearly in the arms 32 and 33 are made upof stacked providing faces are ably slotted and are provided. d shadingwindings 3i and 38, latter being more clearly indi- The d y mountedwithin the air gap s 35 35 and, as illustrated, the shaft is journalledwithin provided in housing Li-i depending from latter plate is fastenedby to the stator arms 32 and 33, and is insulated therefrom byinsulating spacers i i. It is to be understood that all motor partsexcept the rotor and the steel laminations of the fiux collector armsare of a non-magnetic material.

The outer extremity of the flux collector arm 33 extends at right angleswith respect to the pole portion 33 thereof and projects upwardly withinthe centr'..- opening 29 beyond the ends of the impeller blades. "Theother arm 32 is straight and extends outwardly beneath the lower windingsection and, as illustrated, the outer extremity thereof may be embeddedin the base portion 25 for anchoring the motor securely in position.

Upon the energization of the reactor coils, a magnetic field will be setup encircling the windings and due to the high permeability pathprovided by the flux collector arms 32 and 33, a certain amount of thefield flux will circulate through the arms providing excitation for themotor as indicated by the dotted line 46 in Fig. 6. The flow of fluxthrough the motor poles and rotor is the same as that in theconventional shaded pole fractional horsepower motor, the function ofthe shading coil being the same in each instance. As illustrated in Fig.5, the shaded pole portions 41 and 48 of the main poles 35 and 36,respectively, produce a flux which lags the flux of the main poles by acertain angle and results in a relatively weak revolving field to give asmall starting torque to the rotor 34. Rotation of the rotor-is in thedirection of the main pole toward the shaded section and is indicated bythe arrow 49. .The size and shape oi the flux collectors are correctlyproportioned to divert a proper amount of flux. By this arrangement,when the current through the winding being cooled increases, more fluxpasses through the motor, fan speed increases, and a larger the lowerend of the reactor core, it is obvious that the motor may be arranged inany other suitable position with respect thereto. For example, in Fig.'7 the motor 51 is shown arranged at an intermediate point within thecore, the outer ends of the flux collecting arms 52 and 53 extending inopposite directions so as to provide a suitable high permeability pathfor a portion of the flux oi. the reactor field. In Fig. 8 the motor 54is shown mounted at the upper end of the reactor with one of the fluxcollecting arms 55 extending downwardly into the core opening while theother arm 56 extends laterally across the top of the winding.

It is obvious that the invention is not limited to the use or only asingle pair 01' poles for the motor but any other suitable number ofpoles may be provided. In the preferred embodiment illustrated in Figs.9 and 1G, a four-pole motor is provided having diametrically oppositeflux collecting arms 66 and 65 similar to the arm 33, and diametricallyopposite flux collecting arms =38 and 51 similar to the arm 32. The polefaces of these arms are provided with shading coils as described inconnection with the preceding modifications.

Having described the principle of operation of my invention togetherwith the apparatus which I now consider to represent the best embodimentthereof, I desire to have it understood that the apparatus shown ismerely illustrative and that the invention may be carried out by othermeans.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination with a supporting structure for a reactor windingincluding a plastic base member, said structure having a ventilatingopening extending axially therethrough, a ventilating fan arrangedwithin said opening, a motor for driving said fan comprising a rotormember and a pair of cooperating magnetic stator members, one of saidstator members extending into said opening parallel with the axisthereof, the other of said stator members extending radially of saidreactor and embedded in said base member.

2. A cooling system for a single-phase air core reactor winding embeddedin a plastic supporting structure and having an axial openingtherethrough, said system comprising an impeller arranged within saidopening ior forcing cooling fiuid over said winding, a motor for drivingsaid impeller comprising a pair of spaced apart aligned magnetic fluxcollector arms arranged longitudinally within the magnetic field of saidwinding, at least one of said arms being embedded in saidsupportingstructure, and a rotor arranged between and rotatably supported uponsaid spaced apart arms.

ERNEST A. EDGE

